The invention is concerned with an apparatus and a process for edge processing of a glazing, and a glazing, such as an automotive glazing, comprising a processed edge.
It is known in the field of processing glass panes, such as vehicle windscreens, to provide a processed edge using a rotating wheel, such as a grinding wheel. A wheel suitable for glass panes has an annular groove in its circumference, having a shape corresponding to a desired edge shape of the glass pane. A glass pane is arranged in a plane of the annular groove and is brought into contact with the groove, to define a contact region. As the contact region moves along the groove, glass material is removed by grinding. An orifice such as a nozzle is provided to supply coolant to the glass pane.
U.S. Pat. No. 4,739,586 (Eckardt/Flachglas) discloses two coolant jets arranged in a plane of a groove, for injecting coolant tangentially into the groove, so that a contact region receives coolant from both directions along the groove. Coolant is injected in a fine jet so that a relatively limited quantity of coolant is required.
U.S. Pat. No. 4,667,443 (Sakurai/NSG) discloses a single nozzle arranged above a glass pane, for injecting coolant to an edge of the pane. Grinding pressure is controlled to provide a glazing having a desired edge shape and a uniform margin. Examples of edge shape are chamfered and U-shaped. An example of a glass pane is a windshield glass of a vehicle.
U.S. Pat. No. 5,713,784 (Miller) and U.S. Pat. No. 6,287,176 (Volgt/Wendt) both disclose a water container for supplying cooling water to a grinding region via a nozzle, or a series of nozzles, arranged only on one side of a plane of a groove in a grinding wheel.
WO2003080290A1 (Collins/AP-Technoglass) discloses a single nozzle for directing coolant generally towards an edge processing wheel. The coolant further serves to lubricate a contact region. Edge processing is said to have three benefits (a) to remove sharp portions (‘burrs’) of an edge which could cause injury when handling a glass pane, (b) to reduce small fractures in the edge that could otherwise cause shattering of the glass pane and (c) to produce an aesthetically pleasing product.
JP2003266306A, WO2003076132A1 and JP2010058265A (Bando/Bando) disclose a container for supplying coolant via first and second series of holes. The first series of holes is arranged perpendicular to the glazing for supplying coolant to the glazing, in a region adjacent to a contact region where the glazing contacts a grinding wheel. The second set of holes is arranged in a plane of a groove in a circumference of the grinding wheel for supplying coolant to the groove.
U.S. Pat. No. 6,196,902 (Gazca-Ortiz/Vidrio) discloses an apparatus for processing an edge of an automotive glazing, having a grinding wheel and a means for distributing a cooling fluid, which comprises two tubes arranged on opposite sides of the wheel, each having a plurality of holes. The holes are for projecting coolant fluid towards the periphery and lower and upper surfaces of the wheel. Cooling fluid is preferably projected as a spray or a mist. Spray is said to be an improvement over a flow of water, because a spray prevents glass being stained with debris from grinding, which is carried over an edge of the glass by the flow of water.
There remains a need for an alternative apparatus and an alternative process for edge processing to achieve the above-mentioned benefits in a corresponding product.